Device for starting and scavenging two-cycle engines.



R. we.

DEVICE FOR STAR'HNG AND SCAVENG|NGTWO-CYCLE ENGINES.

APPLICATION FILED OCT. 20' 1915.

1,259,398. PatentedMm-JZJQB.

3 SHEETS-$HEET 1.

. R. HENNlG'.

DEVICE FOR STARTENG AND SCAVENGING'TWO-CYCLE ENGINES.

APPLICATION FILED ocT. 20. I915.

1,259,398. Patented Mar. 12, 1918 3 SHEETS-8HEET 2- Inventor. w y- By Y a. HENNEG. DEWCE FOR ST ARHPJQ MID SCAVENGING TWO-CYCLE E'NGiNESl APPLICATION FILED OCT. 2% l9l5- Patented 1131.12, 1918.

3 SHEIITS-SHEET 3.

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, 272322 502: I 3 9M M v Pa W UNITED STATES PATENT OFFICE.

RUDOLF HENNIG, 0F HAMBURG, GERMANY, ASSIGNOB TO GEEK... PAGLOW, OF

' KL. GRASBROOK, NEAR HAMBURG, GERMANY.

DEVICE FOR STARTING AND SOAVENGIN G TWO-CYCLE ENGINES.

I Specification of Letters Patent. I Pate ted Mar. 12, 1918.

Application filed Oct0be1'20, 1915. Serial 87,021.

subject of the German. Emperor, and resi.-

dent of Hamburg, Germany, have invented '5 certain new and useful Improvements in Devices for Starting and scavenging Two- Cycle Engines, whereof the following is a specification.

The present invention refers to a device for starting and intensified scavenging by means of a scavenging pump in two stroke cycle engines, the object. bein to arrange the parts so that there will e a minimum consumption of compressed air when starting; furthermore to feed the scavenging air, compressed by the scavengfgingpiston, by avoiding large spaces for its accumulation, as directly and as completely as possible to the working cylinder through ume. so as to obtain by this an intensified scavenging of the working cylinder for the purpose of increasing thv output.

By means'of the hitherto known arrangements of scavenging pumps in two cycle engines this result cannot be attained.

The scavenging pum'psbft'wo cycle en-. glues are, as a rule, provided with admission organs (suction valves, flaps, slides, ports and the like) and with exhaust or, gans of a similar construction. ing of the scavenging air is effected from the scavenging pumpsto a special receptaclc or a piping of comparatively great ce paeity wherein the scavenging air is stored under moderate pressure. p

In. engines in which scavenging air, is compressed in the crank case as is common in single acting engines, the exhaust organ of the scavenging pump is constituted by ports in the working cylinder, which ports are positively opened by the working piston when the same reaches the end of the flzxplosion stroke. In this case the crank case forms a voluminous compression space and haste be especially packed at its joints to prevent leakage.

l urthermore, it iscustomary in both cases to employ a check valve in the passage from the cranlr case to the intake port of the cylinder to prevent the products of corn- -bustion finding their way into the crank case and thus contaminating the scaveng ing air. 11

is furthermore known thatby means of ports or passages having a minimum vol.

The feed thesecheck valves a so-called prolonged scavenging may be attained, because the admission ports are at the least as long as or longer than the exhaust ports, whereby an increased quantity of air can be supplied to the working cylinder and thereby an in creased output be obtained.

Finally, when the scavenging pump is employed for' starting the engine with compressed air, on account of the large spaces existing in the two first named devices, considerable quantities of compressed starting air required. I

According to the, present invention the results mentioned at the beginning of this specification are attained in-a simple and a manner that a small consumption of so starting compressed air and an intensified positive scavenging of the working cylinder.

'with pure scavenging air and with a mimlnuni of loss is rendered possible. For the purpose of obtaining a further reduction 35 the consumption of compressed air, it is advantageous to give the passages from the. st Venging pump to the engine'c-ylinder the least possible dimensions and to arrange the exhaust valves as near to the scavengin% air cylinder as. possible.

he object of the present invention is 's'ch'en'iatically shown byway of example in the drawing,in which- Figure 1 shows the cylinders in verticalgs longitudinal section.

Fig. 2 shows the corresponding horizontal-section of the same.

Fig. 3 is a sectional view of-a check valve used herewith in closed position. Fig. 4: is a similar view'with-the valve I 1 Fig. 5 is a diagrammatic view'showing th device for admitting starting air and for operating the mechanism which -holds the 10! of the scavenging air cylinder S, comprisin a double actlng piston D. The three cy inders form a united casting. Furthermore a a, and 0,, c, are the exhaust ports 5 and the admission ports respectively of the working cylinders.

The scavenging air cylinder is provided with the ports g, through which (in case of a correct working of the engine) the outer. .air enters and through which, when startmg 1s effected by compressed air, the ex.-

laust air is exhausted in known manner z'see also Fig. 2).

' From the scavengingair pump two upper ports 0 0," and two lower ports u,, a lead to the'admission ports 6,, e, of the working cylinder. In these ports four check valves "are mounted, which valves open a d the admission ports'e and 6, respectively.

Each of these check valves comprises a stem-c surrounded by a sleeve f having a head f at one .end forming a'seatfor a valve spring m. This head fits in the end of'a cup-s aped valve b having afiange at its open end arranged to fit a respective valve seat.

The devices 70,, it, between intended for the purpose of pressing said check valves 5,, 5 when the engine is started,

80 down upon their seats and to release them when the engine is running. At the same time'they serve the spring plates of these 'valves' as supports when said valves are released. The devices 70,, k 'may, as is shown 435 in Fig. 2, be simultaneously turned by means of levers and rods, whereby the rollers 1' 7*, are lifted from the valves or pressed against the same. Furthermore the devices k is, partiallyfill the objectionable spaces 40 intheports e e said spaces being prefer abl of reduced dimensions Elach'of these devices is, and 7?, consists of a rotatable disk it whereon are journaled the rollers i", and m. The handle h is pivoted on a fixed pin it and engages with its free lower end a tubular camshaft splined on a valve operating shaft *0. On this cam shaft are cams g and g which are adapted to engage the stems of valves '5 c', i, and 2', when the cam shaft is moved to the right 01 left, but when the cam shaft i in its central. position, thgcams are free from the valve stems as shown in Fig, 5. These valves remain closed while, at the same time, the jc-neck valves are'free. to open so that the engine works in its-normal manner. The tube w/is in communication with a reservoir containing compressed air, while the tubes w 'w w, and w, lead!the'compressed air to thefour cylinders V V,, D

and S of the engine. l

The three driving cranks of the pistons are set at a hown t 1, Q'and 3 in Fig. 1. For a good operation of theengine it is 623 essential that the objectionable'spaces 0,, 0

the valves are to the left or to the right respectively. By 75 this movement the cams q or g respectively are brought in line with the spindles of the valves 71,, '5 rand '11,, and one of the valves is opened by the corresponding cam.-' If the parts of the engine before tarting have the position shown -in Fig. 1, the valve 2', or i, is opened by operating the handle it. Said handle turns also the devices k is, in such a manner, that the rollers r 7', hold the check valves 1;, and Z7, closed.

As soon as the engine has reached the necessary speed, the handle it is brought into the position shown in Fig. 5, the fuel is conveyed to theengine and the normal working of the latter begins.-

he normal. operation of the engine is as follows:

When the crank 3 is about 60 in front of its lowest position the piston T opens the ports a, and 8,. As soon as the pressure of the exhaust gases has become less than the pressure of the air compressed by the downward stroke under the piston D, the lower valve b, is lifted and the compressed air streams through the cylinder V Prior to the opening of the ports a, and e, the scavenging air piston D moving upward has shut the ports 9 and has compressed the air over itself. Therefore the upper valve 6 opens sometime after the lower valve 5 and the air compressed over the piston D passes through the cylinder V, until the piston '1, again shuts the ports a, and a,

The remainder of the air compressed above the piston D serves .for accelerating the scavenging of the cylinder V by entering, throughthe top valve 6 this cylinder after its exhaust, similarly to the action above described with reference to the air below the piston Dpassing into the cylinder V,.

What I claim as my invention and desire to secure by United States Letters Patent is t 1. In combination, a twocycle engine having a cylindenan air pump, a conduit for conveying air compressed by said pump to scavenge the cylinder of said engine, a check valve located in said conduit, said valve having an adjustable spring plate, means for startin the engine by compressed air, and a device or pressing-said spring plate against said valve to close positively said valve dur: ing the starting. 2. In combination, a two-cycle engine having a crank shaft'providedwith cranks at right angles to each other, and a pistonconnect-ed to one of the cranks of said shaft, an air pump havinga piston connected to the remaining crank, a conduit for conyeying air compressed by saidpump to scavenge the cylinder of said engine, a check valve located in said conduit, said valve having an adjustable spring plate,'means for starting the engine by compressed air, and a dc vice for pressing said spring plate against said valve to close positively saidvalve during the starting.

In combination, a two-cycle engine hav ing. a cylinder, an air pump, a conduit of small. volume leading from said pump to the cylinder of said engine for conveying com"- presscd air to scavenge said cylinder, :1 check valve located in said conduit, said valve having an adjustable spring plate, means for starting the engine by compressed air, and a device for pressing said spring plate against said valve to close positively said valve during the starting.

4. In combination a two cycle engine having a pair of cylinders, an air-pun1p located between said cylinders, conduits for convey-i ing air con'ipressed by said pump to scavenge each of said cylinders, a check valve located in each of said conduits, valve having an adjustable spring plate, means for starting the engine by compressed air, and a device for pressing said spring plate against said valve to close positively said valve'during the starting.

5.111 combination, a two-cylinder tw0- cycle engine having a pair of pistons, a crank shaft having a pair of cranks arranged at 180 and a third crank at 90" to the others, c'oi'inectio between the pistons and the pair of crane, an air pump located be tween said cylinders and having a piston connected to the third crank, conduits for conveying air compressed by said pump to scavenge each of said cylinders, a check valve located in each of said conduits, means for starting the engine by cinnpressed air, and means for positively closing said valves during the starting.

6. ln combination, a two-cycle engine havinga pair of cylinders, an air-pump located between said cylinders and having a piston adapted to compress air on both sides thereof, conduits of small. volume leading from each side of said piston to each of said cylinders for conveying air compressed by said pump to scavenge each of said cylinders, a check valve located in each of said conduits, means for starting the engine by compressed air, and means, sin'iultaneously operative with the starting means, for positively closing all. of said valves during the startin In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses,

RUDOLF HENN 1G.

Witnesses: I

GUSTAV LAMBERTZ, i JULIUS HAND. 

